Vaishali R. Choksi

The sensitivity and specificity of electrodiagnostic testing for the clinical syndrome of lumbar spinal stenosis

Study Design. Prospective, masked, double controlled diagnostic trial. Objectives. To determine the sensitivity and specificity of electrodiagnostic consultation (EDX) for the clinical syndrome of lumbar spinal stenosis. Summary of Background Data. EDX has been used for more than 50 years to diagnose spinal disorders but has not met the new standards of evidence-based medicine. Methods. A total of 150 subjects (asymptomatic volunteers and patients with MRIs suggesting back pain or spinal stenosis; 55–80 years of age) underwent physiatrist history and physical examination, MRI, and review of this data by a neurosurgeon, with each clinician masked to any outside information, leading to a unanimous consensus on diagnosis in 55. After masked EDX testing, 7 subjects with undiagnosed neuromuscular disease were discovered. EDX findings were related to “clinical gold standard” diagnoses in 48 persons. Results. Paraspinal mapping EMG score of >4 had 100% specificity and 30% sensitivity for stenosis compared with either the back pain or asymptomatic groups (each, P < 0.04). A composite limb and paraspinal fibrillation score had a sensitivity of 47.8% and specificity of 87.5% (P = 0.008), and H-wave sensitivity was 36.4, specificity 91.3 (P = 0.026) for stenosis versus all controls. Conclusions. This first masked study in the 60-year history of needle electromyography also introduces anatomically validated needle placement, quantified and reproducible examination of the paraspinal muscles, and dual control populations to EDX research in spinal disorders. EDX has statistically significant, clinically meaningful specificity for spinal stenosis and detects neuromuscular diseases that may masquerade as stenosis.

Efficiency of a Semiautomated Coding and Review Process for Notification of Critical Findings in Diagnostic Imaging

OBJECTIVE When a significant unexpected finding such as malignancy is noted on a study, the standard of care generally holds that the radiologist communicate the findings to the referring physician and document the communication in the radiology report. Despite this standard, for a variety of reasons it remains possible that the direct care provider might receive such notification but not initiate an appropriate workup. On the basis of prior root cause analysis, we developed and instituted a semiautomated process for notification of critical diagnostic imaging findings. We now report our 12-month experience with the process. MATERIALS AND METHODS A diagnostic code was attached to every radiology report. When a significant unexpected finding occurred, our radiologists, in addition to contacting the appropriate clinician, gave the report the designation code 8. On a weekly basis, a list of code 8 cases was passed to the cancer registrar at our institution, who tracked the cases to ensure that they were appropriately followed up. RESULTS In the 12-month period after initiation of this system, we performed 37,736 radiologic examinations at our institute. Of these, 395 cases were given code 8. All code 8 cases were followed up by the tumor registrar. In 35 cases, no workup was documented after 2 weeks. Of these, eight cases would have been completely lost to follow-up if this safety net had not been in place. CONCLUSION Failures of communication, documentation errors, and various system failures may lead to an untoward outcome for the patient. We devised a simple system to ensure that significant unexpected findings on imaging received appropriate attention. An additional level of redundancy has increased the probability of optimal patient outcome.

Magnetic resonance imaging vs. electrodiagnostic root compromise in lumbar spinal stenosis: a masked controlled study.

Chiodo A, Haig AJ, Yamakawa KSJ, Quint D, Tong, H, Choksi VR: Magnetic resonance imaging vs. electrodiagnostic root compromise in lumbar spinal stenosis: a masked controlled study. Objective:The high false-positive rate of magnetic resonance imaging (MRI) makes it a less-than-reliable tool for evaluating clinically significant stenosis. Finding MRI changes that correlate with electrodiagnostic abnormalities might lead to more successful treatment decision making. The purpose of this study was to identify MRI changes that correlate with neurologic abnormalities measured by electrodiagnosis in patients with spinal stenosis. Design:One hundred fifty persons with and without back pain between the ages of 55 and 79 yrs participated in this prospective, blinded, controlled study. Exclusion criteria included previous spine surgery or known neuropathy. Needle electromyography of the limb, nerve conduction studies, including peroneal F-wave and tibial H-wave, and noncontrast lumbo-sacral spine MRI were completed. A codified physical medicine and rehabilitation history and physical examination was completed to differentiate symptomatic lumbar stenosis patients from asymptomatic controls. The relationship between lumbar MRI measurements and extremity electromyography findings was studied. Results:MRI measurements did not differ significantly with respect to extremity needle electromyography findings in the entire population or in patients with clinical signs of lumbar stenosis. In the entire population, an absent tibial H-wave corresponded to the interfacet ligament distance at L5–S1 and anterior to posterior canal size at L4–5. In patients clinically evaluated as having lumbar stenosis, peroneal F-wave latency correlated with anteroposterior canal size at L4–5 and interfacet ligament and anterior to posterior lateral recess narrowing at L5–S1. In patients with clinical signs and symptoms of lumbar stenosis, limb electromyography findings did not correlate with MRI measurements, although H-wave and F-wave testing correlated with relevant locations of stenosis. Conclusions:Needle electromyography does not differentiate patients with symptomatic mild or moderate lumbar stenosis. However, H-wave and F-wave correlated to specific anatomical changes on MRI in this patient population.